Protective "Blast Cage"?

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Gerry52

Gerry52

Member
Oct 13, 2017
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Oceanside,California, United States
When I was a firefighter we filled our own SCBA'S. Tanks were placed in a protective steel mesh cage while filling in case of tank structural failure. I'm thinking of building one. All my tanks are in great shape & hydrotested when required but we ALL know doodoo happens. After all, we ARE dealing with explosively high pressures. Anybody here use one or fabricated one? How'd you do it? 
 
How often do SCBA and other HPA tanks used for PCPs "explode"?

Just curious as I don't own any tanks. Only a hand pump.
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I say it’s pretty rare if you use high quality tanks and hydro tested every 5 years and not drop them and don’t fill fast and pass 4500psi…..,,



I fill to 4200 psi only and have hydro cert and will have it retested soon so I think I’m safe but one can never know, it’s a lot of pressure. 
 
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They all have burst discs. Something would have to be catastrophically wrong with the tank, and most likely visible, for it to explode before the burst disc blew out and released the air. 

High pressure air is scary and things do happen but they are safe. As long as they’re visually inspected regularly and hydro tested when they should be, most problems can be avoided.

Stoti
 
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I'm sure the occurrence of SCBA tanks bursting is extremely rare. I've worked with HP cylinders for almost 30 years but knowing what I do about the damage they COULD cause & the fact that every time I fill the odds are ONE MORE TIME more likely for a mishap, no matter my safety precautions, I think I'd rather err on the safety side. I've never been a gambler. Luck doesn't favor me in that regard (though I AM very lucky in other areas of my life) I just figured another safety precaution couldn't hurt. An exploding tank, however rare the possibility, COULD!!! Just something to think about. Be smart, stay safe & shoot straight people. I care about you all.

Gerry 
 
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SCBAs by design will not fail catastrophically. Rescue personnel wear these on their backs. I don't believe you can blow up an SCBA with any compressor available to home users. Some other fitting would fail first...
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"Some other fitting would fail first... "-and this has been documented on this forum, with pictures in one case. Wear safety glasses and use caution.
 
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SCBAs by design will not fail catastrophically. Rescue personnel wear these on their backs. I don't believe you can blow up an SCBA with any compressor available to home users. Some other fitting would fail first...
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I thought I had read that somewhere. Seems that even a structural failure of the tank itself would not likely result in an "explosion". Unless the damage was sudden or due to extreme heat as in a fire and even then, I have seen video of a HPA tank being shot with a high power PB rifle and it did not explode. It DID, however, become a projectile.

The rapid release of HPA can cause it to become a projectile and the rapid release of HPA itself can at least be awakening!

I experienced blowing a 4500psi rupture disc (Nova Vista Freedom, MUCH smaller volume than SCBA or HPA tank) and I certainly was awake after the event! LOL!

So, it seems to me that making something to secure the tank so that it can never gain velocity if ruptured is a better route than a "cage" where there may be enough room for it to gain enough momentum to break free of said cage? Just thinking out loud... (grin)

Does anyone have links to evidence of SCBA or HPA actually exploding? I mean, like in a bomb type of explosion?
 
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I've told this story before elsewhere on the forum. When I was a boy in the 1950s my father was stationed on Guam. He decided to take up scuba diving when tanks were still made out of steel.

One day one of the guys who had his tanks stored in his garage knocked the tank over and broke the neck off the valve off the neck.

The garages were made out of cinder block. The tank went across the garage through the wall and a quarter of a mile down the street where it went through the wall and into a different garage on a different house.

Now that probably was a 200 bar tank not a 300 bar tank.

Doesn't prove anything but you sure wouldn't want that to happen inside of a cargo container on an aircraft.

That does suggest that tying it down is most important thing you can do. I had a burst disc fail on a CO2 bottle a large CO2 bottle on a paint marker once while I was driving. That was exciting.
 
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I've told this story before elsewhere on the forum. When I was a boy in the 1950s my father was stationed on Guam. He decided to take up scuba diving when tanks were still made out of steel.

One day one of the guys who had his tanks stored in his garage knocked the tank over and broke the neck off the valve off the neck.

The garages were made out of cinder block. The tank went across the garage through the wall and a quarter of a mile down the street where it went through the wall and into a different garage on a different house.

Now that probably was a 200 bar tank not a 300 bar tank.

Doesn't prove anything but you sure wouldn't want that to happen inside of a cargo container on an aircraft.

That does suggest that tying it down is most important thing you can do. I had a burst disc fail on a CO2 bottle a large CO2 bottle on a paint marker once while I was driving. That was exciting.
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Good story! And I think it does prove one thing. At least the anecdotal evidence is that the greatest risk with ANY failure of HPA tanks is becoming a projectile. Also, along with tying it down securely, I would suggest making sure that there is nothing nearby that could become a projectile by the sudden release of HPA.

Mostly, just follow safe handling rules and procedures and NEVER stray from them.
 
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I've told this story before elsewhere on the forum. When I was a boy in the 1950s my father was stationed on Guam. He decided to take up scuba diving when tanks were still made out of steel.

One day one of the guys who had his tanks stored in his garage knocked the tank over and broke the neck off the valve off the neck.

The garages were made out of cinder block. The tank went across the garage through the wall and a quarter of a mile down the street where it went through the wall and into a different garage on a different house.

Now that probably was a 200 bar tank not a 300 bar tank.

Doesn't prove anything but you sure wouldn't want that to happen inside of a cargo container on an aircraft.

That does suggest that tying it down is most important thing you can do. I had a burst disc fail on a CO2 bottle a large CO2 bottle on a paint marker once while I was driving. That was exciting.
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Most tanks in the 1950,s were not even 200 bar, but more like 175 bar. My dad told me a similar story, but it was a large compressed air cylinder at Hickam AFB that got its valve knocked off and it wen t thru a wall and across the 1/4 mile parking lot and through a cinder block wall in a warehouse. Either way, I suspect they would have tended to spin more than go straight. I did once see a paintball tank levitate a couple feet off the ground like a missile landing slowly for awhile when the valve broke, it then spun and cartwheeled til it ran down.
 
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I found this video a while back, i sure as hell would not like to be in there with that bottle.

https://youtu.be/XJuIwHJTCbY

I am unsure if this is some form of AIO setup, it sort of look that way'



I have painted quite a few airplane tire filling cages ( powder coating ) those things feel quite solid.

If i was filing bottles myself and had the space, i would make some form of protection for sure, just to be on the safe side and as fabricating in Metal is one of my educations. And if i had the room for it fabricating tools like welders ASO i would also have of course.
 
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@Chickenthief, not really overthinking it. Just 70 yrs old & seen more crap happen in life than I could ever have imagined. As this activity becomes more popular & more & more people are getting compressors & tanks the "odds" are in more in favor of something bad happening. Not OVERthinking, just THINKING about it. That's why I asked other's opinions. 

BTW the "cage" I spoke about was about 10"x 10" x 36" height. Tank just drops right into it.
 
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Firstly, I want to make it clear that I'm for safety first when dealing with anything that could be harmful to me or others. That said, the premise that a HPA compressor a shooter might have at home is capable of catastrophically blowing up an SCBA is "over blown". No way, no how. They are "engineered" to split, not BURST apart killing the rescue personnel that wear them daily. What retailers filling tanks do is very different (liability issues) vs. a home user. The emphasis should be on tethering your fill whips, making sure probes are in good shape, foster fittings, etc. Using your compressor in a space with no one else in the room, etc. Basic safety protocols. All the above based on my basic understanding of HPA. Not claiming any expertise in the matter.
 
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